The entire disclosure of Japanese Patent Application No. 2001-167600 filed on Jun. 4, 2001 and Japanese Patent Application No. 2001-167601 filed on Jun. 4, 2001 including specification, claims, drawings and summary is incorporated herein by reference in its entirety.
1. Field of the Invention
This invention relates to a tunnel excavating machine, such as a shield excavator or a tunnel boring machine, for excavating the soil and assembling covering members, such as segments, onto the inner wall surface of the soil to construct a tunnel.
2. Description of Related Art
In a general tunnel excavating machine, a cutter head is rotatably mounted in a front portion of an excavating machine body. Many cutter bits are fixed to the front surface of the cutter head, while a ring gear is fixed to a rear portion of the cutter head, and a drive gear of a drive motor mounted on the excavating machine body is in mesh with the ring gear. A plurality of shield jacks are arranged parallel in a circumferential direction in a rear portion of the excavating machine body. The shield jacks are stretched rearward in an excavating direction and pressed against existing segments, so that the excavating machine body can be moved forward by a reaction force generated thereby.
An erector device is provided in the rear portion of the excavating machine body, and the erector device mounts new segments in a space between the excavating machine body advanced by the shield jacks and the existing segments, and assembles the new segments in a ring shape. Furthermore, a rest extends rearward from the rear portion of the excavating machine body, and the rest is provided with a segment assembly scaffold for bolting the segments assembled by the erector device, and a shape retainer for retaining the ring-shaped segments in a predetermined shape (for example, a round shape).
Thus, when the shield jacks are stretched with the cutter head being rotated, the excavating machine body is advanced by the reaction force resulting from the pushing of the shield jackets against the established segments, whereupon the cutter head excavates the soil lying ahead, forming a tunnel. Then, the erector device assembles segments in a ring form to the inner wall surface of the resulting tunnel. An operator bolts the segments to each other while standing on the segment assembly scaffold, and the shape retainer corrects the ring-shaped segments to a predetermined shape and retains them in this shape.
With the above-described conventional tunnel excavating machine, the erector device and a cage of the segment assembly scaffold move in the circumferential direction within the constructed tunnel. Thus, the erector device and the cage of the segment assembly scaffold are disposed in a displaced manner relative to each other in a fore-and-aft direction in order to prevent their interference with each other. In this case, while the erector device is holding the segments and locating and retaining them at predetermined positions, the operator needs to ride on the cage and move near the segment assembly position, and then carry out an operation for bolting the segments together with the use of a tool. However, the erector device and the cage are displaced from each other in the fore-and-aft direction. Thus, the operator riding on the cage is spaced by a predetermined distance from the bolting site of the segment, having difficulty in performing the bolting operation.
The present invention has been accomplished in an attempt to solve the above-mentioned problems. Its object is to provide a tunnel excavating machine which increases the efficiency of an assembly operation for a covering member.
According to the present invention, there is provided a tunnel excavating machine, comprising:
a cylindrical excavating machine body;
propulsion jacks for moving the cylindrical excavating machine body forward;
a cutter head rotatably mounted in a front portion of the excavating machine body;
an erector device mounted in a rear portion of the excavating machine body and adapted to assemble covering members in a ring form onto an inner wall surface of an existing tunnel;
a rest extending rearward from the rear portion of the excavating machine body;
a revolving frame located behind the erector device and supported on the rest so as to be movable along a fore-and-aft direction of the existing tunnel such that the revolving frame does not interfere with the erector device; and
a working platform supported on the revolving frame so as to be revolvable in a circumferential direction of the existing tunnel.
Thus, the working platform can be brought close to the covering members assembled by the erector device. Hence, the operator can easily perform a bolting operation, and the work efficiency of a segment assembly operation can be increased.
In the tunnel excavating machine of the invention, a shape retainer for making pressurized contact with inner peripheral surfaces of the covering members assembled onto the inner wall surface of the existing tunnel to retain the covering members in a predetermined shape may be provided and supported on the rest so as to be movable along the fore-and-aft direction of the existing tunnel, and the revolving frame may be located between the erector device and the shape retainer and supported on the rest so as not to interfere with the erector device and the shape retainer.
Thus, the working platform can be brought close to the covering members assembled by the erector device, without interference of the working platform with the shape retainer. Hence, the operator can easily perform a bolting operation.
The tunnel excavating machine of the invention may further comprise working platform revolving means for moving the working platform to a predetermined revolving position, erector revolving position detection means for detecting a revolving position of the erector device, and working platform control means for setting a working position of the working platform adapted for the revolving position of the erector device and controlling the working platform revolving means.
Thus, the working platform can be brought close to the covering members assembled by the erector device, easily and in a short time, without interference of the working platform with surround instruments. Hence, the operator can easily perform a bolting operation, and the work efficiency of a segment assembly operation can be increased.
In the tunnel excavating machine of the invention, the working position of the working platform may be at a revolving angle from a horizontal reference position, and the revolving angle may be set by adding or subtracting a preset given angle to or from a revolving angle of the erector device from the horizontal reference position.
Thus, the revolving angle of the working platform can be set easily, and the working platform can be moved to the working position easily.
In the tunnel excavating machine of the invention, the given angle may have been set in accordance with the revolving angle of the erector device.
Thus, the working platform can be moved to a position close to the erector device, regardless of the revolving position of the erector device.
In the tunnel excavating machine of the invention, the working platform may be supported in a horizontal state regardless of the revolving position of the working platform, and the working platform control means may set the working position of the working platform, where the erector device and the working platform are close to each other at a constant distance, regardless of the revolving position of the erector device.
Thus, the operator can easily perform a bolting operation, regardless of the revolving position of the erector device.
In the tunnel excavating machine of the invention, the revolving frame may be moved back and forth, whereby the working platform can be moved into and out of a revolving range of the erector device.
Thus, the working platform can be moved close to the erector device, with interference of the erector device and the working platform being prevented.
In the tunnel excavating machine of the invention, the working platform control means may be constituted such that an operation by an operator controls the working platform revolving means to move the working platform to the working position and stop the working platform at the working position.
Thus, operability for moving the working platform can be increased.
In the tunnel excavating machine of the invention, the working platform may have a working step protruding forward.
Thus, the operator can easily move forward with the use of the working step, and carry out a bolting operation for the covering members adjacent in the fore-and-aft direction.
In the tunnel excavating machine of the invention, the working step may be constituted by a front wall portion of the working platform pivoted forward.
Thus, a working space on the working platform can be widened easily with a simple structure.
In the tunnel excavating machine of the invention, the working step may be constituted by a bottom portion and a front wall portion of the working platform sliding forward.
Thus, a working space on the working platform can be widened easily, with sufficient safety of the operation being ensured.